Cardiac ablation is a therapy used to treat cardiac arrhythmias. An ablation procedure involves identifying abnormal cardiac tissue from which an arrhythmia is arising or creating a circulating pathway for conduction of the arrhythmia then ablating the cardiac tissue to eliminate a focal point of origin or recirculating pathway. The ablation energy is typically RF ablation though chemical ablation or cyroablation can be used. Ablation therapy is used to treat patients who experience arrhythmias that are refractory to medication, experience serious side effects from medications used to treat arrhythmias, or experience serious or life-threatening arrhythmias.
The clinician has the task of properly identifying a targeted site for ablation that will successfully eliminate the abnormal tissue. The process of identifying an ablation site can include 12-lead ECG studies, electrical mapping using intracardiac electrodes, and may require inducing abnormal rhythms in order to identify and confirm an arrhythmia and an appropriate ablation site. In some cases, the ablation may be incomplete, not entirely eliminating the occurrence of associated arrhythmia episodes. Some patients may experience more than one type of arrhythmia, arising from more than one focal point or reentrant circuit. The procedure for identifying the proper ablation site and the correct number of ablation sites to satisfactorily reduce the occurrence of arrhythmias in a given patient is a challenge to the clinician.
Implantable cardiovertor defibrillators (ICDs) are also used to treat patient's experiencing arrhythmias. ICDs do not eliminate the abnormal tissue causing arrhythmias to occur but can deliver cardiac pacing, anti-tachycardia pacing or cardioversion/defibrillation shocks to prevent or terminate an arrhythmia episode. ICDs typically acquire data relating to an arrhythmia episode when it does occur, including, for example, an intracardiac electrogram (EGM) strip, cardiac cycle lengths measured during the episode, EGM signal morphology data, data relating to the onset of the episode, and therapies delivered to treat an arrhythmia.
Patients receiving ICDs may experience a high occurrence of shock therapies which are painful and can reduce the quality of life of the patient. Ventricular ablation can be used in ICD patients that experience recurrent ventricular tachycardia (VT) or VT storms to reduce the number of shocks required by the ICD. Data stored by an ICD relating to sustained or non-sustained VT can include information useful to a clinician performing ablation procedures. Data stored by an ICD can be uplinked to an external ICD programmer for manual review and analysis by a clinician performing an ablation, however the large amount of episode data can pose considerable data analysis burden on the clinician. What is needed therefore, is a system and method that provides a clinician information acquired by an ICD in a useful format to assist the clinician in efficiently and effectively performing an ablation procedure.